Mine is a PE story, too. I've always been on the heavier side and as an added bonus, I've really not athletic. I could manage to hold my own when we were doing sports like volleyball or badminton (kind of, if I remembered to wear my glasses to gym so I could see the birdie). However, there was no hope for me with running.
Our track was 1/4 mile around, so on "Mile Day" we'd have to run four times around it. The class would have to wait for the last person to finish up before going back in. I was much slower than the rest, even when putting out my best effort. I'd be somewhere in the middle of lap 3 when the rest of the class was done, and the teacher would still make me finish. Being exhausted by this point, I would be going even slower than the first few laps.
The day I remember best was when one of the smart alec kids was yelling "encouragement" at me, like "Hurry up you (blanking) fat (blank)! No one wants to watch your rolls wiggle anymore!" He was standing about 2 ft from the teacher and I was halfway down the track away. If I could hear him, the teacher could, but he didn't do anything about it.
Luckily, my parents were the sort who believed me and they went up to the school the next day after that, told the teacher off, and fixed it so I only needed to do 3 laps instead of 4, so I'd finish up at the same time as the rest of the class. It was still so miserable after that incident that I got a doctor's note to get out of PE the last 4 years of school.